It is previously known to strive to prevent the effect of electromagnetic interference. Shieldings are implemented by protecting the device or some parts of the device with casings or compartments or partitions of an electrically conductive material. If the casing of the device comprises a plurality of mechanically interconnected parts, these structures require an electrically conductive gasket to seal the gaps of the joining points. Such a gasket is called an EMC or EMI gasket.
The gasket does not necessarily have to constitute an integral continuous conductive circle between the electrically conductive pieces. If the gasket does not constitute an integral conductive circle, then, however, the mutual gaps of the separate conductive areas comprised by the gasket have to be dimensioned such that the gasket provides sufficiently high attenuation, i.e. isolation. One factor affecting the dimensioning is the radio frequency radiation wavelength or the wavelength half, but, in practice, however, if the radio frequency radiation wavelength is for instance some decimeters, then the gaps of the successive conductive areas of the gasket are, however, clearly shorter, i.e. 2 to 10 mm.
The gasket is particularly required because, as regards the manufacturing accuracy of the mating surfaces of the pieces to be connected, they are not necessarily as straight as would be optimal, but somewhat arched or otherwise such that galvanic insulation is not realized without a gasket.
Previously known gaskets are of the metal spring type or flexible, i.e. elastic gaskets made from an electrically conductive rubber or some other material. In a gasket having a metal spring structure, a banded thin metal ring therein comprises partly projecting claw-like spring projections cut off from said banded material, which improve the compression of the gasket between the connectable parts and thus constitute an electrically conductive connection also in places where the gap between the connectable parts could otherwise keep the connectable parts galvanically apart. Said gasket made from a metal band and provided with a claw-like projection spring can be manufactured in a plurality of ways. One way is to cut an aperture in a metal gasket band, by etching or with a tool, the aperture extending through the gasket band, followed by bending said spring-like claws to project from the basic structure of the band-like gasket. A way is also known wherein both the cutting and the bending are performed with the same tool.
Several problems are associated with prior art solutions. The gaskets are relatively expensive and laborious to manufacture, which complicates their use. Problems become emphasized in possibly even very labyrinthine gasket structures comprising a plurality of compartments or blocks. The above problems relating to the structure of the gasket and the cost of manufacture are associated with the manufacture of a conventional metal gasket, which is provided with bent, projecting claw springs cut off from a metal band. A special tool for bending is required in the manufacture of a conventional metal gasket provided with bent, projecting claw springs cut off from a metal band. Said special tool is extremely expensive, as much as 200,000 USD because of the small-sized scale of the object it is used on. If a less expensive simpler bender were used, then the achievement of the spring claws would be a work step requiring significantly much time.
Publication U.S. Pat. No. 6,451,374 discloses an implementation wherein a conductive sealant paste is sprayed directly onto the surface of either connectable piece as separate sealant paste areas, i.e. as drops, for example. However, said solution involves problems, since the structure of the sealing cannot be changed, and the sealing is in no way changeable, since no actual separate gasket component exists, only sealing material drops provided in the pieces to be connected or in one of them.
Furthermore, a solution (Laird Technologies) is known, wherein a sealing conductor pattern of a conductive material is printed directly onto the product or on top of the carrier material, but in said solution, the conductive sealant paste is on top of the sealing carrier structure, i.e. the sealing carrier structure is closed at the point whereto sealant paste has been applied. This results in the drawback that the material of the sealing carrier structure also has to be electrically conductive in order for the sealant paste to be involved in generating a conductive connection from one side of the carrier structure to the other, and thus, in practice, from a first connection piece of the electronic device to a second connection piece. Alternatively, if the carrier structure is not electrically conductive, the coating on top of the carrier material has to encircle the carrier structure on all sides, i.e. also from the sides, not only from the actual mating surfaces on the sides of the connectable structural parts in the sealing structure, since otherwise a gap of the breadth of the entire sealing structure, which would eliminate the EMC/EMI shielding, remains also between the mating surfaces of the sealing structure and, thus, also the connection parts of the electronic device. Whether an electrically conductive carrier structure or an electrically non-conductive carrier structure coated all around with an electrically conductive coating is concerned, said known sealing manner results in higher manufacturing costs and, as concerns environmental issued, poor recycling, since a carrier structure coated all around, such as a rubber carrier structure, for example, is not recyclable.